wabt

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Previously an indexed ref type was parsed as a Var, assuming that regular types would be represented as index vars and indexed ref types would be named vars. The names would be resolved to actual indices later in a separate pass.

Unfortunately, it's also possible for a ref type to be an indexed var that overlaps with a type (e.g., the type "any" which is 0x0 and the index 0 for the type (ref 0)).

This patch fixes the issue by returning both a Type and a Var from ParseValueType.

Edit: I simplified this patch to just solve the issue at hand instead of introducing a bigger re-organization, which I realized was a bad idea.

This PR will close #1881.

Pinging @dbezhetskov in case you have any thoughts on this approach too. :)

I think the idea is that builtin types should all have negative values .. so we know that thing >= to zero is a user type. The fact that we have this internal "Any" think value of zero sounds like a bug.

@takikawa Do you have cycles to respond to this review? Would be nice to get this merged (especially as #1661 is blocked on a bug that this fixes).